Piston structure



p 1945. F. F. CHAMLEE 2,384,533

PISTON STRUCTURE Filed April 20, 1943 2 Sheets-Sheet l Inventor E841? Geam/lee WW w;

Sept. 11, 1945. M E 2,384,533

P I STON STRUCTURE Filed April 20, 1943 2 Sheets-Sheet 2 fiiiiiiiilUflllInventor ?a tente d Sept. 11', 1945 a T when STATES PATENT rrs'roiv's'rnuc'mns Fred F. Chamlee, Gatelville, Tex. Application April 20, 194:,Serial No. 483,773

(on. soc-11) It is the principal object of the present invention in anappreciable manner to correct and alleviate some otithe weak points ofthe present-day internal combustion engine pistons by presenting apiston which will have no slap" action and which will present severalfeatures which will cause a guiding and true movement of the piston withthe result that there will be no undue wear on any particular place ofthe piston.

Another important object of the invention is to provide a piston"structure wherein the head thereof is constructed in an unusual mannerand in a manner complementary to certain other portions of the piston soas to oil'er a unique means for preventing the escape of pressure due touneven wear of the piston in any respect.

Still another important object of the invention is to provide a pistonwhich has certain skirt portions, a head portion and certain expansioncompensating features, all 01 which cooperate to present a piston whichwill retain its precise original shape over a far more considerableperiod oi time than is possible with presentday pistons.

Other objects and advantages of the invention will become apparent tothe reader of the following description.

In the drawings:

Figure 1 represents a side elevational view of the piston located withinthe cylinder, the latter being shown in vertical section.

Figure 2 is a side elevational view of the piston with the oil ring andpiston head rings removed.

Figure 3 is a vertical sectional view on the lin 3-4 of Figure 2.

Figure 4 is a horizontal section on the line 4-4 or Figure 2.

Figure 5 is a fragmentary enlarged sectional view through the headportion of the piston.

Referring to the drawings wherein like numerals designate like parts, itcan be seen that numeral 5 generally refers to the improved piston. thesame being situated in a conventional cylinder 0, as shown in Figure l.

The piston I consists of a head portion I. a re.- duced intermediateportion I and" upper and lower skirt portions 0. l0 situated above andbelow the reduced intermediate portion. I.

In the head I' are' packing ring grooves ,l i. for

accommodating rings l2.

' The upper portion of the piston hasga muitiplicity of verticallydisposed slots "extending from a point just above the skirt Ito a pointjust within the reduced portion I. The purpose of these slots will bemore tuliy brought out hereinai'ter.

At the upper portion of the skirt II is an oil groove for accommodatingan oil ring H.

or importance is the fact, that bearings II, I! for accommodating theusual wrist pin it, on which is the upper bearing of the complementarypiston rod ll, located within the skirt Mainstead of at an intermediateportion oi the piston. In other words, the upper limits or the lines offorce do not pass much beyond the intermediate portion of the piston,with the result that this in itself reduces considerable or the "slapaction of present-day pistons.

Now referring to another important feature. and that is, the downwardslope of the lands II at the head I or the piston. These lands it arepreferably curved downwardly to a substantial point Ila, which pointededge is flush with the peripheries of the aprons 9, ll.

Obviously, there will be considerable more expansion oi the head I ofthe piston than the lower skirt portion iii and to take care of thisditierentiation, the slots it are provided. In other words, theexpansion of the skirt it will be strictly radial, while the expansionof the skirt 8 which would normally be greater than the skirt II is notonly radial but also circumferential in that some or the expansion istaken up by the slots l3. Therefore, it can be seen that as the pistonheats up the fine or substantially sharp edges Ila or the lands It willpress against the wall of the cylinder 6 and wear in uniformly, inasmuchas there is no tendency of the piston to slap as it is being preciselyguarded by the riding action of the skirts Q, l0 against the wall of thecylinder. Thus a compensating or neutralizing means is provided forunequal expansion of diil'erent parts of the piston.

Therefore, it can be seen that while the upper skirt 9 will have agreater ratio of expansion than the skirt it, this increase will beneutralized by the presence of the slots i3 and this feature is takeninto consideration with the tact that the head I will expand most 0! alldue to its extreme hot position and, therefore, at the crit ical heattemperature of the cylinder, the fine edges Ila oi the lands I! willhave worn away just sufilcient enough to snugly wipe the cylinder wall,thus affording a head structure which machines itself into a perfect fitunder the conditions of operating engine heat expansion.

At this point, it should be understood, that when the piston isinitially placed in the cylinder, there is no clearance between the fineedges Ila of the lands l8 and the cylinder wall. Obviously, when theengine is operating and the head I is hot it expands and it is thisfrictional engagement oi the edges Ila which results in the perfectbreaking in of the head in the cylinder, with the cooperation of theguiding skirts 9, i and the specific location of the wrist pin bearingsl6, all of which go together to eliminate slap action which hasheretofore caused irregular wear of pistons.

It can also be observed, that on the down stroke of the piston, thepacking rings will displace lubricant i'rom the cylinder wall and ontothe beveled lands, while on the up-stroke this lubricant is forced bysaid lands against the wall of the cylinder for uniform lubricationbetween the piston and said cylinder well.

While the foregoing specification sets forth the invention in specificterms, it is to be understood that numerous changes in the shape, sizeand materials may be resorted to without departing from the spirit andscope of the invention as claimed hereinafter.

Having described the invention, what is claimed as new is:

1. An internal combustion engine piston comprising a head. a dependingstructure. a skirt just below the head, a skirt at the lower portion 05the structure, and a reduced portion between the skirts, longitudinalslots being provided in said reduced portion extending into said headskirt.

2. An internal combustion engine piston comprising a head, a dependingstructure. a skirt just below the head, a skirt at the lower portion ofthe structure, and a reduced portion between the skirts, and a pistonrod connection at the lower skirt, longitudinal slots being provided ins3; reduced portion extending into said head 8 3. An internal combustionengine piston comprising a head, a depending structure. a skirt justbelow the head, a skirt at the lower portion of the structure, and areduced portion between the skirts, said upper skirt and adjacentreduced portion being vertically slotted parallel to the piston axis.

4. A piston comprising a body having a head portion, said body havingupper and lower skirts, the upper skirt being slotted parallel to theaxis to neutralize unequal expansion between the lower and upper skirt.

5. A piston comprising a body having a head portion, said body havingupper and lower skirts, the upper skirt being slotted parallel to theaxis to neutralize unequal expansion between the lower and upper skirt,the portion of the body between the skirts being reduced in circumfer-

